Conventional composite structures are typically comprised of reinforcing fibers embedded in a matrix. Fiber-reinforced composite structures are typically designed to transmit loads along the length of the fibers. Loads from one fiber may be transferred to another fiber in the same layer or to fibers in an adjacent layer by passing through the matrix material. However, the matrix is typically weaker than the fibers such that when a sufficiently high load is transmitted from one fiber to another fiber across the matrix, the matrix will fail. The failure of the matrix allows the fibers to move within the composite structure.
During a ballistic event wherein a composite panel is impacted by a projectile, the ability of the fibers to move within the matrix may affect the ballistic performance of the composite panel. For example, the ability of the fibers in the matrix to move may affect the resistance of the composite panel to penetration by the projectile. For transparent composite panels, movement of the fibers relative to the matrix may also affect the optical performance of the composite panel. For example, movement of the fibers relative to the matrix during a ballistic event may affect the size of an optically-degraded area of the composite panel as a result of impact by the projectile.
As can be seen, there exists a need in the art for a composite structure wherein movement of the fibers within the matrix can be controlled in a manner such that the ballistic performance of the composite structure may be improved.